In a test of electric characteristics of an integrated circuit (IC) sealed by a package, a mold and the like, is generally used auxiliary means for testing comprising an electrical connecting apparatus called socket. Each electrode of a semiconductor device as a device under test is movably connected to an electric circuit of a testing apparatus such as a tester through this electrical connecting apparatus. This type of electrical connecting apparatus is described in Patent Document 1.    Patent Document 1: Japanese Patent Appln. Public Disclosure No. 8-233900 Official Gazette
The electrical connecting apparatus described in Patent Document 1 comprises a plate-like electrically insulating housing with a plurality of slots penetrating in a plate thickness direction, and a device under test (DUT) board, on which a circuit to be connected to a tester is formed, is attached to the underside of the housing. Also, on the upside of the housing, a semiconductor device to be tested is disposed so that a lead as its electrode may extend toward each slot. Each contact is made of a conductive contact base member and a conductive contact member. The contact, disposed in each slot, is slidable on a guide face of the contact base member. Each contact base member is elastically supported within the slot of the housing so as to be pressed toward the circuit on the board provided on the underside of the housing by the elastic biasing force of two elastic members traversing each slot. Also, both the elastic members exert their elastic biasing force to each conductive contact member. Each conductive contact member is disposed within the housing slidably on the guide face of the corresponding contact base member and is disposed in the housing with its contact end portion projected from the upside of the housing.
Consequently, by pressing the lead of the semiconductor device against the conductive contact member of each corresponding contact, each lead is connected to the corresponding circuit on the board through the contact base member on which the conductive contact member slides, which enables testing by the tester.
In the heretofore electrical connecting apparatus, however, the conductive contact base member and the conductive contact member guided to slide by the conductive contact base member are elastically supported on the housing by the above-mentioned two elastic members. For this reason, when the lead of the semiconductor device is pressed against the conductive contact member for a test, a contact end of the conductive contact member to the lead slides on the lead with the sliding of the conductive contact member. At this time, the conductive contact base member slidably receiving the conductive contact member on the guide face also slides slightly on the circuit of the board.
When the contact end of the conductive contact member slides on the lead, the lead surface is sometimes slightly scraped. However, this is only once at the time of testing and does not cause the lead to have any great damage or abrasion. Moreover, since the oxide film on the lead surface is removed by the sliding, electrical connection between the lead and the contact end of the conductive contact member is ensured, so that this sliding is desirable.
On the other hand, when the conductive contact base member slides on the circuit of the board, the circuit portion is subjected to slight abrasion. However, the board, different from the electrode of the semiconductor device to be tested, is subjected to repeated sliding of the conductive contact base member every time a new semiconductor device is tested. Consequently, the conductive contact base member and the circuit portion of the board on which the conductive contact base member slides are prone to be worn, thereby causing to spoil durability.